1. Field of the Invention
The present invention relates to a drilling rig or drilling device, respectively, in particular a deep drilling device, used in offshore regions, and to a mounting method therefor, wherein the use of this deep drilling device is preferably performed during vertical drilling for the exploitation of deposits. The term “deposit” comprises in particular the existence of a substance in liquid, gaseous, or solid form, or the presence of energetically utilizable conditions in geological structures, in particular with respect to crude oil, natural gas, and geothermal energy.
2. Description of the Related Art
Vertical drilling is used for the exploitation of oil and gas fields, but also for the production of geothermal energy. From the state of the art, a vertical drilling rig of the type VDD 370 by Max Streicher GmbH & Co. KG aA is known, which is illustrated as an example in FIG. 1 and will be described briefly in the following.
The drilling mast 1 is mounted on a pivot bearing 2 so as to be pivotable with respect to the drilling platform 4. This renders it possible to implement an easy and safe assembly of the drilling mast 1. A vertically movable feed carriage 6 comprising a receiving device 8 for drilling rods is fastened to the drilling mast 1. The drilling rods 10 are supplied via a pipe handler 12 and fixed to the receiving device 8 and subsequently introduced into the well bore. The drilling platform 4 is positioned on a substructure 14 comprising a plurality of segments 16 which are stacked side by side and on top of each other.
Such a rig is described in PCT applications PCT/EP2005/000452, PCT/EP2005/000453, PCT/EP2005/000454, and PCT/EP2005/000455. A use of this drilling rig is also possible in the offshore region. In so doing, the drilling rig is either transported to the drilling site in the assembled state, or is assembled at least partially during towage.
While the offshore drilling rig mentioned is provided for being newly constructed at a site, in today's offshore exploitation of oil and gas fields there exist increasing problems in that the drilling rigs of existing platforms are technically obsolete and frequently can no longer be taken into operation, but the exploitation is desired by making use of existing well bores.
The disassembly of existing drilling rigs and the new construction of drilling rigs is time and cost-intensive, in particular due to the large components of the drilling rig which have to be transported across the sea by means of special vessels, and due to the plurality of joining processes to be performed, in particular welding processes.
Moreover, space restrictions, in particular when constructing new drilling masts, exist on established platforms. If a telescopic drilling mast is used, there result disadvantages with respect to the smooth guiding of a feed carriage and with respect to stability in difficult weather conditions.